OPERATIONAL SAFETY ISSUES OF NUCLEAR POWER PLANTS IN JAPAN

摘要

Approximately 30 years have passed since the first Japanese nuclear power plant started operation and, currently nuclear power generation accounts for more than 30% of the total electricity produced in Japan. To secure a stable energy supply and to solve the global environmental problems, the use of nuclear power will continue to increase as an alternative energy to oil. According to the 'Supply Target of Alternative Energy Sources for Oil' decided at a Cabinet Meeting in September 1994, an installed capacity of 70 500 MW and a 42% nuclear share of total electricity generation is projected for the fiscal year 2010. In Japan, securing safety has consistently been the major premise in developing nuclear energy and promoting its utilization. Rigorous safety control has been implemented from the initial design stage and subsequent construction, through to nuclear power plant operation. In implementing these safety controls, it has been common practice to request the opinions of the Atomic Energy Commission and the Nuclear Safety Commission, advisory organizations to the Prime Minister, whenever necessary, and to respect their reports. Through such efforts, the annual rate of incidents and failures at nuclear power plants in Japan has been maintained at a low level. In fiscal 1994, the number of unscheduled shutdowns per unit was 0.3 times per unit per annum. Ageing of nuclear power plants is currently drawing attention as a coming issue in Japan. To continue safe operation of the existing nuclear power plants, every effort is being made to provide countermeasures against ageing, such as the establishment of ageing evaluation methodology, development of related technologies, preparation of technical standards, and the implementation of various tests and periodical safety reviews.